1. Field of the Invention
This invention pertains generally to a valve and more particularly to a fast valve capable of ejecting a plurality of gases, simultaneously.
2. Description of the Related Art
In operations, such as the production of a dense plasma, gas is injected into a chamber. In this type of operation, as well as many others, there is a need for a valve to deliver a puff of gas within a short period. A delay between the valve opening the operation may cause the operation to be unsuccessful.
Currently, a typical valve for use in plasma production operates through the use of diamagnetic repulsion, has only one gas chamber and, therefore, operates with only one gas or gas mixture at a time. This type of valve 10 is shown in FIG. 1 and operates by discharging a capacitor (not shown) into a coil 12 thereby creating a magnetic field that repels an aluminum ring 14 which rests above the coil 12. The ring 14 is allowed to accelerate through a predetermined distance, thereby achieving a large velocity before striking a nylon poppet 16. The poppet 16 is then driven off an O-ring 17, opening the valve 10 and permitting a gas to flow through the gas inlet 18 and out the gas outlet 19. Use of this two stage process of valve opening reduces the rise time when compared with designs using magnetic forces to open the valve directly. Compare, Simple, fast, puff valve, Rev. Sci. Instrum. 62 (10), pp. 2372-2374, Oct. 91; U.S. Pat. No. 4,771,447, Saitoh et al., 1988; Kriesel et al., and Wong et al., Balanced puff valve for imploding gas-puff experiments, Rev. Sci. Instrum, 57(8), pp. 1684-1686, Aug. 86. Some experiments require the use of two gases, therefore, two, separate, independently working fast valves are required to provide concentric gas streams. See, Finken et al., The Gas-Liner Pinch--A New Spectroscopic Light Source, Phy. Ltrs. Vol. 85A, No. 5, pp. 278-280, Oct. 81. However, the use of two valves creates problems with gas rise times which is dependent upon the length that a gas has to travel downstream of the valve. In a two-valve system, one valve has to be displaced farther back or to the side of the other and this requires long flow tubes which in turn causes the gas rise time to be longer. A longer gas rise time allows the gas to diffuse with the other gas or into the chamber and cause electrical breakdown.